Env: ClientExec 7.2.2 (ionCube), PHP 8.5.10, MariaDB 11.8.9. Source WHMCS 9.
Where: plugins/import/whmcs/whmcs2ce.php lines 136 and 157-161
Bug: $_isUtf8 defaults to false and nothing sets it, so _addColumn() runs utf8_encode() on every value. WHMCS 9 data is already UTF-8, so non-ASCII text...